Consideration of General Waveform Creation Method for Road Simulator Durability Test
-Development of Numerical Simulation Modeling Based on a Comparison of Real Vehicle Vibration Testing Accounting for Four Wheels Phase Differences and Numerical Simulations-

Tomoyuki Kita (Press Kogyo)･Atsuhito Nakamura (Mitsubishi Fuso Truck and Bus)･Mitsuo Harino (Suzuki Motor)･Tetsu Oami (Toyota Motor)･Atsushi Yagi･Yuki Ogi (Toyota Auto Body)･Ryo Okabe (Mitsubishi Motors)･Masahiro Kajihara (Honda R&D)･Hisami Oishi･Kousei Fukatsu･Yusuke Kasai (Kogakuin University)

To investigate the influence of vehicle inputs on the four body modes, a four-wheel vertical excitation experiment and a numerical simulation using a four-wheel, seven degrees-of-freedom model were conducted. As a result, it was confirmed that each mode exhibited a different response due to the effect of sprung mass resonance. Furthermore, the necessity of four-wheel validation was identified to investigate the influence of suspension characteristics on vehicle response.

Consideration of General Waveform Creation Method for Road Simulator Durability Test
-Comparison and Investigation of Time History Waveforms Derived from Road Surface PSD and Measured Time History Waveforms-

Takayuki Nakamura (Toyota Motor)･Kouki Satou (SUBARU)･Kohei Mino (Honda R&D)･Yusuke Suzuki (Daihatsu Motor)･Atsuhito Nakamura (Mitsubishi Fuso Truck and Bus)･Ryo Okabe (Mitsubishi Motors)･Syuzo Hirayama (MTS Japan)･Kosei Fukatsu･Yusuke Kasai･Hisami Oishi (Kogakuin University)

A method for separating operational input from market measurement data was refined, and Power Spectral Densities (PSDs) for four road types—highway, normal road, winding road, and rough road—were computed. The obtained PSDs were found to be equivalent to those reported at the 2021 Symposium and the 2023 Spring Conference. It was demonstrated that Unevenness values increased in the order of highway, normal road, winding road, and rough road, which was consistent with the expected characteristics of each surface.

Development of a Method for Predicting Underbody Stress from Road Interference

Yoichiro Okuhira･Takanori Ogata･Takeyuki Harada･Masao Matsumura･Yuya Yamaki (Toyota Motor)

In recent years, vehicle electrification and low-floor design requirements have increased the need for analyzing road surface interference with underbody components. While nonlinear finite element analysis is widely used for short-duration impact phenomena, practical challenges remain when interference occurs in conjunction with vehicle dynamics. This study presents a hybrid approach that combines multibody dynamics analysis with localized nonlinear deformation modeling applied only to interfering components. The proposed method enables accurate and efficient prediction of interference loads within significantly reduced computational time.

Set-Based Design Approach for Vehicle Reliability Development Using Bayesian Active Learning

Kohta Miyaki･Tomotaka Sugai･Koji Nishikawa (Toyota Motor)

In defining the target strength of the vehicle body, the maximum load that the vehicle body can endure is estimated by utilizing a surrogate model based on machine learning, which is created from the vehicle body input from rough-road simulations. However, the response surface of the vehicle body input has a strong nonlinearity, and in utilizing the surrogate model for this purpose,It is essential to accurately predict the maximum values within various ranges of design variables. This paper proposes a new method to learn by focusing on the vicinity of the peaks for responses that are nonlinear and possess multiple local maxima.

Numerical Evaluation of Single Lap Joints Bonded with Adhesive

Hirofumi Sugiyama (University of Yamanashi)･Shigenobu Okazawa (University of Yamanashi/Diver Technology)

This study presents a numerical evaluation method for adhesive-bonded single-lap joints. A previously proposed numerical method was capable of simulating crack propagation, and its applicability had been confirmed under shear deformation. However, the conventional model had limitations in representing the complex mechanical behavior of the adhesive layer and cracks occurring in arbitrary directions. The present study extends this approach to evaluate the adhesive region under bending loads. Numerical simulations of single-lap joints were conducted, and the results demonstrate the capability of the proposed method to reproduce the joint strength and crack behavior.